Sleep apnea's toll on the heart

Health professionals commonly warn about the long-term effects of
sleep apnea on patients’ health, sometimes with great result, but more often
than not, patients fail to fully understand the risks involved and the major
health changes they are about to face. This blog post is part of a series on
disease prevention and management we will be covering in the weeks ahead to
help individuals better assess their sleep health.

I may have sleep apnea… so what?

How would you feel if you had to hold your breath for 10 to 30
seconds every few minutes during daytime for 6-8 hours? Not only would it be
unpleasant, but you might get very tired from undergoing such a repetitive
asphyxia…. After one day of this regimen, you may very well want to stop that
game, knowing it is bad for your heart… and your brain (if any is left from
it!).

This is exactly what you should remind yourself if you have
untreated sleep apnea. Years of recurrent hypoxia during sleep can cause or
worsen high blood pressure, elevate blood lipid levels, contribute to insulin
resistance and diabetes, and markedly increase the risk for heart attack and
stroke. Sleep apnea may also produce ventricular hypertrophy (heart
enlargement) and diastolic dysfunction (inadequate filling of the ventricle) of
the heart, which can eventually progress into heart failure.

Not only may sleep apnea be a cause of congestive heart failure,
but the presence of congestive heart failure may also trigger or exacerbate
sleep-disordered breathing. Below are a few recommendations for you to keep in
mind… and act on!

Sleep apnea may lead to congestive heart failure… if you don’t
address it!

Individuals with sleep apnea have a two-fold risk of developing
congestive heart failure (CHF). Contributing risk factors for sleep apnea
include age, obesity, large neck circumference, craniofacial abnormalities such
as a small lower jaw, sleeping on your back, or the presence of cardiovascular
disease. Current research suggests that Obstructive SleepApnea (OSA) may lead to CHF independent
of age, obesity, or other such common risk factors. Patients with OSA
typically experience many repetitive obstructive breathing events during sleep
exceeding 30 to 60 times per hour, leading to disrupted nocturnal sleep and a
recurrent hypoxia. So if you experience daytime sleepiness or if any of those
risk factors are familiar, get help!

Between 50% to 70% of patients with congestive heart failure
develop a sleep-related breathing disorder. They are at a higher risk of dying
prematurely from these breathing stoppages during sleep as their heart may not
function properly when exposed to repetitive low levels of oxygen in the blood.
Of the patients with CHF who later develop breathing disruptions during sleep,
only a minority of CHF patients develop breathing stoppages from a mechanical
obstruction to the airway as seen in OSA. Instead, the majority of them develop
central sleep apnea, a condition that occurs when the brain fails to transmit
the proper signals to breathe. CHF patients with central sleep apnea typically
experience long apneas, which can last up to 40 seconds and have arousals only
several breaths after the resumption of normal breathing.

A potential problem of the central apneas during sleep is the
negative impact it may have in CHF patients. The hypoxia may worsen the blood
pressure, promote ischemia and worsen existing heart failure by causing
irregular heart beats (arrhythmia). Patients are often tired or sleepy from
poor quality of sleep. A recent study shows that hypoxia in CHF patients
contributes to an overabundance of free fatty acids, which can lead to insulin
resistance, vascular dysfunction, hyperlipidemia and dysfunction of the heart
muscle.

Get treated!

It is essential for individuals with sleep apnea to be evaluated and treated as soon as possible to prevent congestive heart failure from developing or worsening. The gold standard of treatment consists of using Continuous Positive Airway Pressure (CPAP) to open the airway during sleep, which consequently decreases the apneas, improves blood pressure, augments cardiac output, and reduces myocardial oxygen consumption, as well as other cardiovascular complications such as atrial fibrillation. Patients who cannot tolerate CPAP may benefit from an adaptive servoventilation device which performs a breath-to-breath analysis of the patient's respiratory needs, automatically adjusts the amount of airflow it delivers and is especially helpful when central sleep apnea is present. Other treatments include weight loss and oral surgery for patients whose apnea is caused by an anatomical obstruction. Finally, oral appliances are generally not recommended in patients with heart failure, especially for patients with severe sleep apnea.